To help doctors give their patients the best possible care, the American Society of Clinical Oncology (ASCO) and the College of American Pathologists (CAP) developed evidence-based recommendations to improve the accuracy of testing for estrogen and progesterone receptors for breast cancer. This guide for patients is based on ASCO's and CAP's recommendations.

Key Points:

• Estrogen and progesterone receptors are found in breast cancer cells that depend on estrogen and related hormones to grow.
• All patients with invasive breast cancer or a breast cancer recurrence should have their tumors tested for estrogen and progesterone receptors.
• This testing should be performed by an accredited laboratory that follows specific testing procedures and handles the samples in a consistent way.